An ISA, or Individual Savings Account, is a type of savings or investment account available to UK residents in which any interest, dividends or capital growth you earn is free of UK tax. Each tax year you can put money into ISAs up to an annual allowance, which is £20,000 for the 2026 to 2027 tax year according to GOV.UK. A cash ISA works much like an ordinary savings account, but the interest you earn does not count towards your taxable income, which is the key difference.
Key takeaways
- An ISA is a wrapper, not a product in itself. It is a tax-free container that holds either cash savings or investments, depending on the type you choose.
- The annual ISA allowance is £20,000 for the 2026 to 2027 tax year. You can split this between different ISA types, as long as no more than £4,000 goes into a Lifetime ISA (GOV.UK).
- A cash ISA is similar to a normal savings account in that your money is deposited and earns interest, but the interest is not taxed.
- You must be 18 or over to open an adult ISA, and children under 18 can hold a Junior ISA with a separate £9,000 limit (GOV.UK).
- ISAs can be transferred between providers, and GOV.UK states savers have the right to transfer whenever they want, using a formal transfer process rather than withdrawing and redepositing.
What is an ISA and why does the tax treatment matter?
GOV.UK describes ISAs simply as a way to “save tax-free with Individual Savings Accounts”. The account itself is offered by banks, building societies and other providers, but the tax-free treatment comes from the ISA rules. Interest earned in an ordinary savings account is treated as taxable income, whereas interest earned inside a cash ISA is not.
It is worth understanding that for many people with modest savings, tax on savings interest may not actually be an issue. Depending on your income and circumstances, you may be able to earn some savings interest outside an ISA without paying tax on it. GOV.UK explains the allowances, and whether you pay tax depends on how much interest you earn, your other taxable income and your tax-free allowances. A cash ISA becomes most valuable for savers whose interest exceeds those allowances, or who expect it to over time, particularly higher-rate taxpayers.
An ISA is therefore not automatically “better” than a normal savings account. It is a choice that depends on how much you save, your tax position and the interest rates available. This article is neutral education, not a recommendation of any particular account or provider.
What types of ISA are there?
There are several types of ISA, each with its own rules. The main ones relevant to beginners are:
- Cash ISA: a savings account where your money earns interest free of UK tax. Your deposit is not invested in the stock market.
- Stocks and shares ISA: an account in which your money is invested. Any capital growth or dividends are free of UK tax, but the value of investments can fall as well as rise, so you could get back less than you put in.
- Lifetime ISA (LISA): available to adults under 40, designed for buying a first home or saving for later life. You can put in up to £4,000 each year until you turn 50, and the government adds a 25% bonus, up to a maximum of £1,000 per year (GOV.UK).
- Innovative Finance ISA: holds certain peer-to-peer lending and other alternative investments. These carry additional risks, including the risk that borrowers do not repay.
- Junior ISA: a long-term, tax-free savings account for children under 18, with a savings limit of £9,000 in the 2026 to 2027 tax year. The money belongs to the child, who can take control of the account at 16 but cannot withdraw until 18 (GOV.UK).
This guide focuses mainly on cash ISAs, since that is the type most comparable to an everyday savings account.
How does the ISA allowance work?
Each tax year, running from 6 April to 5 April, you can subscribe (pay in) up to the annual limit across your ISA accounts. For the 2026 to 2027 tax year, GOV.UK sets the overall limit at £20,000. A few practical rules apply:
- You can split your £20,000 between different ISA types, but no more than £4,000 of it can go into a Lifetime ISA (GOV.UK, guidance on managing ISA subscriptions).
- The £4,000 Lifetime ISA limit counts towards the overall £20,000 allowance, not on top of it.
- You cannot hold an adult ISA jointly with someone else; each ISA belongs to one person.
- Each tax year the allowance refreshes. Unused allowance does not roll over to the next year.
- From 6 April 2027, any ISA account receiving a subscription will need a National Insurance number, or a declaration that the investor is not eligible for one (GOV.UK).
A worked example of splitting the allowance
Suppose you have £20,000 to save in a single tax year and you want some flexibility. One possible split would be £4,000 into a Lifetime ISA (claiming the maximum £1,000 government bonus), £11,000 into a cash ISA and £5,000 into a stocks and shares ISA. The total is exactly £20,000, and no single type has been overpaid. If instead you put £5,000 into a Lifetime ISA, you would have breached the £4,000 sub-limit even though you stayed under £20,000 overall. Checking each sub-limit, not just the headline figure, is the detail many beginners miss.
What changed in the Autumn Budget 2026?
You may have read that the cash ISA limit would fall to £12,000 for under-65s from 6 April 2027. That plan was announced in the 2025 Budget, but Hargreaves Lansdown reports that it was cancelled in the Autumn Budget on 28 October 2026, and Deloitte reports that the £20,000 limit will be kept, using legislation due to be laid in November 2026. Check GOV.UK for the current position before you act on any change.
How is a cash ISA different from an ordinary savings account?
In most practical respects, a cash ISA behaves like any other savings account. You deposit money, the provider pays interest, and you can usually choose between easy access and fixed-term versions. The differences come down to tax, rules and flexibility:
Here is a simple comparison:
- Tax on interest: GOV.UK states that you can save tax-free with an ISA. In an ordinary savings account, whether interest is taxable depends on your overall income and the tax rules in force for the year; check GOV.UK for the current position.
- Allowance limits: cash ISAs are capped by the annual £20,000 ISA allowance. Ordinary savings accounts have no limit on how much you can deposit.
- Flexibility: some ISAs are “flexible”, meaning you can withdraw and replace money within the same tax year without using up more of your allowance, but this depends on the provider’s terms. Ordinary accounts have no equivalent restriction.
- Access and rates: rates and access terms vary between both types, and there is no rule that one always pays more than the other. Comparing current rates matters more than the label on the account.
One useful way to think about it: an ordinary savings account gives you unlimited deposits but taxable interest (unless you stay within your allowances), while a cash ISA gives you tax-free interest but a capped annual contribution.
Who can open an ISA?
According to GOV.UK, you must be 18 or over to open an adult ISA, and you need to be a UK resident. There are exceptions for Crown servants, such as members of the armed forces or diplomats, and their spouses or civil partners, who may be eligible even if they do not live in the UK. You cannot hold an ISA with someone else.
If you are opening a Lifetime ISA, there are extra conditions: your first payment must be made before you turn 40, and you can keep paying in until you are 50. After 50 you can no longer pay in or earn the government bonus, though the account stays open and your savings continue to earn interest or returns (GOV.UK).
For children under 18, a parent or guardian with parental responsibility can open a Junior ISA and manage it, but the money belongs to the child. A child cannot hold both a Junior ISA and a Child Trust Fund; if a trust fund exists, it must be transferred into the Junior ISA (GOV.UK).
Can you move an ISA to a different provider?
Yes. GOV.UK guidance states that investors have the right to transfer their ISA whenever they want, and this right must be included in the provider’s terms and conditions. The important detail is that a transfer must be done through a formal transfer application to the new provider. If you simply withdraw the money and pay it into a new ISA yourself, the withdrawal uses up your allowance and you cannot get it back.
Transfers between cash, stocks and shares, and innovative finance ISAs can be made freely. Transfers out of a Lifetime ISA to another type of ISA are treated as a withdrawal and may incur a withdrawal charge, whereas transfers between two Lifetime ISAs do not (GOV.UK). This matters because Withdrawing from a Lifetime ISA for purposes other than buying a first home or saving for later life may mean losing the government bonus and could trigger a withdrawal charge, so it is worth reading the rules carefully before committing money to one (GOV.UK).
Transferring is also worth considering periodically, because cash ISA rates can differ significantly between providers over time. The tax-free status of your ISA stays intact when you transfer properly.
What should beginners check before opening a cash ISA?
Because this is education rather than a recommendation, the best approach is to compare accounts against your own circumstances. A practical checklist:
- Confirm your allowance is available. Check how much you have already subscribed to ISAs this tax year across all providers, so you do not exceed the £20,000 limit.
- Decide easy access versus fixed term. Easy access accounts let you withdraw at any time; fixed-term accounts typically restrict access in exchange for a set rate.
- Check whether the ISA is flexible. If you might need to withdraw and replace money, a flexible ISA preserves your allowance. Not all providers offer this.
- Compare the interest rate and how long it lasts. Some accounts pay a bonus rate for an introductory period only.
- Check deposit protection. The Financial Services Compensation Scheme protects eligible deposits up to £120,000 per person, per bank, building society or credit union. The limit rose to that level on 1 December 2025. Some brands share a banking licence, so check before you deposit large sums.
- Read the withdrawal terms before you commit. Fixed-term accounts in particular can impose penalties or refuse early access.
- Consider whether you need an ISA at all. If your savings interest is comfortably within your personal savings allowance, an ordinary account may serve you equally well and may offer better rates.
FAQ
Do I pay tax on money I take out of a cash ISA?
No. Withdrawals from a cash ISA are not taxed, because the tax benefit applies while the money sits in the account; the interest has already been earned tax-free. However, with non-flexible ISAs, money you withdraw cannot be replaced in the same tax year without using more of your current allowance (check your provider’s terms).
What happens if I do not use my full ISA allowance?
Unused allowance is lost for that tax year. Each new tax year you receive a fresh allowance of £20,000 for 2026 to 2027. Any money already in your ISAs stays there and continues to be tax-free regardless of how much you added in past years.
Can I have more than one ISA?
You can hold multiple ISAs of different types and with different providers, and you can split your overall £20,000 ISA allowance between them in a tax year (GOV.UK). For example, you could pay into a cash ISA and a stocks and shares ISA in the same year, splitting your allowance between them, as long as the total stays within the £20,000 limit (GOV.UK).
Is a Lifetime ISA worth it for a first home?
It depends on your situation. The 25% government bonus is a genuine benefit for eligible first-time buyers, but the £4,000 annual cap, the age limits and the charges for withdrawals not used for a first home or later life mean it does not suit everyone. GOV.UK’s Lifetime ISA page sets out the full rules. If your goals are uncertain, reading those rules before committing money is sensible.
Where can I get regulated advice about saving and investing?
MoneyHelper, the government-backed guidance service, offers free, impartial guidance on saving and ISAs, and can point you towards a regulated financial adviser if you want personal advice. For tax questions, GOV.UK and HMRC are the authoritative sources. This site is educational only and does not recommend specific products.
Final thoughts
An ISA is fundamentally a tax-efficient wrapper for your savings or investments, and a cash ISA is its simplest form: savings with tax-free interest and a capped annual allowance of £20,000 for 2026 to 2027. Whether one suits you depends on how much you save, your tax position and the rates on offer, so it pays to compare rather than assume. If you are also working on the wider foundations of your finances, our guide to what APR means on a UK loan advert is a good companion read, and if you are clearing debt before building savings, our article on what a credit report shows and who can see it explains the records lenders use.
Sources
- Lifetime ISA: Overview – GOV.UK
- Individual Savings Accounts (ISAs): Overview – GOV.UK
- Junior Individual Savings Accounts (ISA): Overview – GOV.UK
- Information you need from investors when they apply for an ISA – GOV.UK
- How to manage ISA subscriptions – GOV.UK
- Transfer an ISA if you’re an ISA manager – GOV.UK
- FSCS: Banks, building societies and credit unions
- GOV.UK: Tax on savings interest
This article is general information and educational only. It is not financial advice and does not recommend any account or provider.
This article is general educational information, not personal financial advice. Capital is at risk when investing; speak to a regulated financial adviser about your own situation.
